Machines are typically designed to perform a variety of different operations, such as, for example, work cycles that may be performed repetitively. According to one example, a work cycle for a wheel loader may include a plurality of work cycle segments, i.e., a dig segment, a reverse lift segment, a forward lift segment, a dump segment, a reverse lower segment, and a forward lower segment, performed sequentially. It should be appreciated that performance of each work cycle segment may require a different amount of power from a power source, such as an internal combustion engine, of the machine. For example, the dig segment or reverse lift segment, performed while the machine is loading and/or carrying a payload, may require more power than the reverse lower segment, performed while the bucket is empty. Oftentimes, however, an operator of the machine may select a constant engine speed, such as a high engine speed corresponding to a high power output, to perform all of the work cycle segments, or operations, of the machine.
Operating the machine at a high engine speed or, rather, a high number of revolutions per minute normally leads to high fuel consumption. Although there has been a desire to increase the productivity of work operations of the machine, it should be appreciated that there may be times when the high engine speed and, thus, high fuel consumption of the machine are not contributing to the productivity of the machine. For example, a high power output and, as a result, high fuel consumption may be required to achieve a high productivity level for some machine operations, but not all. Therefore, it may be desirable to reduce engine speed and, as a result, fuel consumption when it is not significantly contributing to a desired productivity level.
U.S. Patent Application Publication No. 2006/0276948 teaches a control method and device for automatically changing a power output capacity of an engine of a machine between a high output mode and a low output mode. Specifically, a determination is made as to whether excavation or uphill travel is being performed and, if so, the engine is controlled to operate at a high output capacity. While performing any other operation, the engine is controlled to operate at a low output capacity. Although this control method may serve to reduce fuel consumption when operating at a low output capacity, it does not provide flexibility based on current power demands of the machine, regardless of the operation being performed. As should be appreciated, there is a continuing need for control schemes that reduce fuel consumption without adversely affecting productivity.
The present disclosure is directed to one or more of the problems set forth above.